Every time you look, the developers at Flying Lab Software are implementing some new skill, change or system into Pirates of the Burning Sea. Now that their Avatar Combat changes are hitting the mix, the devs have decided to introduce a new optional skill line into the game called Brawling. Here's a portion of the official write-up:

Enter the Brawling skill line. Brawling bases its damage off your equipped weapon, but doesnt care which kind of weapon you have. This is somewhat of a compromise, in that wed like to create brawling weapons that function similarly to guns, but we dont feel like we can provide enough interesting content or customization for those weapons. However, it means that Brawling has a reasonable progression of damage throughout your career.

Brawling isnt so powerful that you absolutely must have it. Across the board, Brawling skills do slightly less damage than weapon and gun skills (on average, theyre -20% damage below other skills). This means it isnt a must-have skill line in a pure dps build. It also provides no persistent buffs or defensive improvements, so it isnt critically important to a pure tank build.

So where are the critical points in Brawling? The first is Jab, which is an attack with a stacking debuff that cannot be parried. It is low damage, but its also free to use. In combination with the second Brawling skill, Cross, you can sustain a stack of 4 debuff effects on a target indefinitely, or with another brawler the two of you can maintain that stack with just the Jab.